Self-Driving Car Engineer Nanodegree

Project: Finding Lane Lines on the Road


In this project, you will use the tools you learned about in the lesson to identify lane lines on the road. You can develop your pipeline on a series of individual images, and later apply the result to a video stream (really just a series of images). Check out the video clip "raw-lines-example.mp4" (also contained in this repository) to see what the output should look like after using the helper functions below.

Once you have a result that looks roughly like "raw-lines-example.mp4", you'll need to get creative and try to average and/or extrapolate the line segments you've detected to map out the full extent of the lane lines. You can see an example of the result you're going for in the video "P1_example.mp4". Ultimately, you would like to draw just one line for the left side of the lane, and one for the right.

In addition to implementing code, there is a brief writeup to complete. The writeup should be completed in a separate file, which can be either a markdown file or a pdf document. There is a write up template that can be used to guide the writing process. Completing both the code in the Ipython notebook and the writeup template will cover all of the rubric points for this project.


Let's have a look at our first image called 'test_images/solidWhiteRight.jpg'. Run the 2 cells below (hit Shift-Enter or the "play" button above) to display the image.

Note: If, at any point, you encounter frozen display windows or other confounding issues, you can always start again with a clean slate by going to the "Kernel" menu above and selecting "Restart & Clear Output".


The tools you have are color selection, region of interest selection, grayscaling, Gaussian smoothing, Canny Edge Detection and Hough Tranform line detection. You are also free to explore and try other techniques that were not presented in the lesson. Your goal is piece together a pipeline to detect the line segments in the image, then average/extrapolate them and draw them onto the image for display (as below). Once you have a working pipeline, try it out on the video stream below.


Combined Image

Your output should look something like this (above) after detecting line segments using the helper functions below

Combined Image

Your goal is to connect/average/extrapolate line segments to get output like this

Run the cell below to import some packages. If you get an import error for a package you've already installed, try changing your kernel (select the Kernel menu above --> Change Kernel). Still have problems? Try relaunching Jupyter Notebook from the terminal prompt. Also, consult the forums for more troubleshooting tips.

Import Packages

In [1]:
#importing some useful packages
import matplotlib.pyplot as plt
import matplotlib.image as mpimg
import numpy as np
import cv2
%matplotlib inline

Read in an Image

In [2]:
#reading in an image
image = mpimg.imread('test_images/solidWhiteRight.jpg')

#printing out some stats and plotting
print('This image is:', type(image), 'with dimensions:', image.shape)
plt.imshow(image)  # if you wanted to show a single color channel image called 'gray', for example, call as plt.imshow(gray, cmap='gray')
This image is: <class 'numpy.ndarray'> with dimensions: (540, 960, 3)
Out[2]:
<matplotlib.image.AxesImage at 0x1d46b3f4518>

Ideas for Lane Detection Pipeline

Some OpenCV functions (beyond those introduced in the lesson) that might be useful for this project are:

cv2.inRange() for color selection
cv2.fillPoly() for regions selection
cv2.line() to draw lines on an image given endpoints
cv2.addWeighted() to coadd / overlay two images cv2.cvtColor() to grayscale or change color cv2.imwrite() to output images to file
cv2.bitwise_and() to apply a mask to an image

Check out the OpenCV documentation to learn about these and discover even more awesome functionality!

Helper Functions

Below are some helper functions to help get you started. They should look familiar from the lesson!

In [3]:
import math

# img: is a colored input image read by mpimg
def grayscale(img):
    """Applies the Grayscale transform
    This will return an image with only one color channel
    but NOTE: to see the returned image as grayscale
    (assuming your grayscaled image is called 'gray')
    you should call plt.imshow(gray, cmap='gray')"""
    return cv2.cvtColor(img, cv2.COLOR_RGB2GRAY)
    # Or use BGR2GRAY if you read an image with cv2.imread()
    # return cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
    
def canny(img, low_threshold, high_threshold):
    """Applies the Canny transform"""
    return cv2.Canny(img, low_threshold, high_threshold)

def gaussian_blur(img, kernel_size):
    """Applies a Gaussian Noise kernel"""
    return cv2.GaussianBlur(img, (kernel_size, kernel_size), 0)

def region_of_interest(img, vertices):
    """
    Applies an image mask.
    
    Only keeps the region of the image defined by the polygon
    formed from `vertices`. The rest of the image is set to black.
    `vertices` should be a numpy array of integer points.
    """
    #defining a blank mask to start with
    mask = np.zeros_like(img)   
    
    #defining a 3 channel or 1 channel color to fill the mask with depending on the input image
    if len(img.shape) > 2:
        channel_count = img.shape[2]  # i.e. 3 or 4 depending on your image
        ignore_mask_color = (255,) * channel_count
    else:
        ignore_mask_color = 255
        
    #filling pixels inside the polygon defined by "vertices" with the fill color    
    cv2.fillPoly(mask, vertices, ignore_mask_color)
    
    #returning the image only where mask pixels are nonzero
    masked_image = cv2.bitwise_and(img, mask)
    return masked_image


def draw_lines(img, lines, color=[255, 0, 0], thickness=2):
    """
    NOTE: this is the function you might want to use as a starting point once you want to 
    average/extrapolate the line segments you detect to map out the full
    extent of the lane (going from the result shown in raw-lines-example.mp4
    to that shown in P1_example.mp4).  
    
    Think about things like separating line segments by their 
    slope ((y2-y1)/(x2-x1)) to decide which segments are part of the left
    line vs. the right line.  Then, you can average the position of each of 
    the lines and extrapolate to the top and bottom of the lane.
    
    This function draws `lines` with `color` and `thickness`.    
    Lines are drawn on the image inplace (mutates the image).
    If you want to make the lines semi-transparent, think about combining
    this function with the weighted_img() function below
    """
    for line in lines:
        for x1,y1,x2,y2 in line:
            cv2.line(img, (x1, y1), (x2, y2), color, thickness)

def hough_lines(img, rho, theta, threshold, min_line_len, max_line_gap):
    """
    `img` should be the output of a Canny transform.
        
    Returns an image with hough lines drawn.
    """
    lines = cv2.HoughLinesP(img, rho, theta, threshold, np.array([]), minLineLength=min_line_len, maxLineGap=max_line_gap)
    line_img = np.zeros((img.shape[0], img.shape[1], 3), dtype=np.uint8)
    draw_lines(line_img, lines)
    return line_img

def get_hough_lines(img, rho, theta, threshold, min_line_len, max_line_gap):
    """
    `img` should be the output of a Canny transform.
        
    Returns lines with hough lines drawn.
    """
    lines = cv2.HoughLinesP(img, rho, theta, threshold, np.array([]), minLineLength=min_line_len, maxLineGap=max_line_gap)
    return lines

# Python 3 has support for cool math symbols.

def weighted_img(img, initial_img, α=0.8, β=1., γ=0.):
    """
    `img` is the output of the hough_lines(), An image with lines drawn on it.
    Should be a blank image (all black) with lines drawn on it.
    
    `initial_img` should be the image before any processing.
    
    The result image is computed as follows:
    
    initial_img * α + img * β + γ
    NOTE: initial_img and img must be the same shape!
    """
    return cv2.addWeighted(initial_img, α, img, β, γ)

Test Images

Build your pipeline to work on the images in the directory "test_images"
You should make sure your pipeline works well on these images before you try the videos.

In [4]:
import os
os.listdir("test_images/")
Out[4]:
['solidWhiteCurve.jpg',
 'solidWhiteRight.jpg',
 'solidYellowCurve.jpg',
 'solidYellowCurve2.jpg',
 'solidYellowLeft.jpg',
 'whiteCarLaneSwitch.jpg']

Build a Lane Finding Pipeline

Build the pipeline and run your solution on all test_images. Make copies into the test_images_output directory, and you can use the images in your writeup report.

Try tuning the various parameters, especially the low and high Canny thresholds as well as the Hough lines parameters.

1.Converting test images into gray scale

In [5]:
import glob
import pylab
images_full_paths_lst = glob.glob('./test_images/*.jpg')
for img_full_path in images_full_paths_lst:
    img = mpimg.imread(img_full_path)
    
    img_gray = grayscale(img)
    
    fig = plt.figure(figsize=(26, 12))
    fig.suptitle("image path: " + str(img_full_path), fontsize=20)
    plt.subplot(121)# 1 row, 2 cols, and this is the first figure
    plt.imshow(img)
    plt.title('Original RGB Image',fontsize=20)
    
    plt.subplot(122)# 1 row, 2 cols, and this is the second figure
    plt.imshow(img_gray, cmap='gray')
    plt.title('Gray Image',fontsize=20)
    
    img_name = img_full_path.rsplit('\\', 1)[1]
    pylab.savefig('test_images_output/grayout_' + img_name) #save the output images into the output images folder
    
    plt.subplots_adjust(top=1.3)
    plt.show()

2.Apply gaussian filter to blur the image

In [6]:
# parameters to tune
kernel_size = 5
In [7]:
for img_full_path in images_full_paths_lst:
    img = mpimg.imread(img_full_path) # read in a colored image
    
    img_gray = grayscale(img) # convert image into gray scale
    img_blured = gaussian_blur(img_gray, kernel_size) # apply gaussian to the grayed image
    
    fig = plt.figure(figsize=(26, 12))
    fig.suptitle("image path: " + str(img_full_path), fontsize=20)
    
    plt.subplot(121)# 1 row, 2 cols, and this is the first figure
    plt.imshow(img_gray, 'gray')
    plt.title('Gray Image Image',fontsize=20)
    
    plt.subplot(122)# 1 row, 2 cols, and this is the second figure
    plt.imshow(img_blured, cmap='gray')
    plt.title('Blurred Gray Image',fontsize=20)
    
    img_name = img_full_path.rsplit('\\', 1)[1]
    pylab.savefig('test_images_output/gaussianout_' + img_name) #save the output images into the output images folder
    
    plt.subplots_adjust(top=1.3)
    plt.show()

4.Apply Canny edge detection

In [8]:
# parameters to tune
low_threshold = 50
high_threshold = 150
In [9]:
for img_full_path in images_full_paths_lst:
    img = mpimg.imread(img_full_path) # read in a colored image
    
    img_gray = grayscale(img) # convert image into gray scale
    img_blured = gaussian_blur(img_gray, kernel_size) # apply gaussian to the grayed image
    img_canny = canny(img_blured, low_threshold, high_threshold) # apply canny edge detection to the blurred image
    
    fig = plt.figure(figsize=(26, 12))
    fig.suptitle("image path: " + str(img_full_path), fontsize=20)
    
    plt.subplot(121)# 1 row, 2 cols, and this is the first figure
    plt.imshow(img_blured, 'gray')
    plt.title('Blurred Gray Image',fontsize=20)
    
    plt.subplot(122)# 1 row, 2 cols, and this is the second figure
    plt.imshow(img_canny, cmap='gray')
    plt.title('Canny Edges Image',fontsize=20)
    
    img_name = img_full_path.rsplit('\\', 1)[1]
    pylab.savefig('test_images_output/cannyout_' + img_name) #save the output images into the output images folder
    
    plt.subplots_adjust(top=1.3)
    plt.show()

5.Apply polygon region of interest

In [10]:
# parameters to tune
diff  = 2
diffx = 50
diffy = 40
In [11]:
def get_polygon_region_of_interest_verticies(imshape):
    ysize = imshape[0]
    xsize = imshape[1]
    vertices = np.array([[(diffx,ysize),(xsize/2 - diff, ysize/2 + diffy), (xsize/2 + diff, ysize/2 + diffy), (imshape[1]-diffx,imshape[0])]], dtype=np.int32)
    return vertices
In [12]:
for img_full_path in images_full_paths_lst:
    img = mpimg.imread(img_full_path) # read in a colored image
    
    img_gray = grayscale(img) # convert image into gray scale
    img_blured = gaussian_blur(img_gray, kernel_size) # apply gaussian to the grayed image
    img_canny = canny(img_blured, low_threshold, high_threshold) # apply canny edge detection to the blurred image
      
    vertices = get_polygon_region_of_interest_verticies(image.shape) # get 4 verticies for the polygon for the region of interest
    img_masked = region_of_interest(img_canny, vertices) # apply the poygon region on the canny image
    
    fig = plt.figure(figsize=(26, 12))
    fig.suptitle("image path: " + str(img_full_path), fontsize=20)
    
    plt.subplot(121)# 1 row, 2 cols, and this is the first figure
    plt.imshow(img_canny, 'gray')
    plt.title('Canny Edges Image',fontsize=20)
    
    plt.subplot(122)# 1 row, 2 cols, and this is the second figure
    plt.imshow(img_masked, cmap='gray')
    plt.title('Canny Edges Image with region of interest',fontsize=20)
    
    img_name = img_full_path.rsplit('\\', 1)[1]
    pylab.savefig('test_images_output/regionofinterestout_' + img_name) #save the output images into the output images folder
    
    plt.subplots_adjust(top=1.3)
    plt.show()

6.Apply hough transform to find the best line that fits the points

In [13]:
#parameters to tune
rho = 2
theta = np.pi/180
threshold = 15
min_line_len = 10
max_line_gap = 50
In [14]:
for img_full_path in images_full_paths_lst:
    img = mpimg.imread(img_full_path) # read in a colored image
    
    img_gray = grayscale(img) # convert image into gray scale
    img_blured = gaussian_blur(img_gray, kernel_size) # apply gaussian to the grayed image
    img_canny = canny(img_blured, low_threshold, high_threshold) # apply canny edge detection to the blurred image
      
    vertices = get_polygon_region_of_interest_verticies(image.shape) # get 4 verticies for the polygon for the region of interest
    img_masked = region_of_interest(img_canny, vertices) # apply the poygon region on the canny image
    
    img_lines = hough_lines(img_masked, rho, theta, threshold, min_line_len, max_line_gap) # draw lines on the masked image
    
    fig = plt.figure(figsize=(26, 12))
    fig.suptitle("image path: " + str(img_full_path), fontsize=20)
    
    plt.subplot(121)# 1 row, 2 cols, and this is the first figure
    plt.imshow(img_masked, 'gray')
    plt.title('Canny Edges Image with region of interest',fontsize=20)
    
    plt.subplot(122)# 1 row, 2 cols, and this is the second figure
    plt.imshow(img_lines, cmap='gray')
    plt.title('Hough transform lines Image',fontsize=20)
    
    img_name = img_full_path.rsplit('\\', 1)[1]
    pylab.savefig('test_images_output/houghout_' + img_name) #save the output images into the output images folder
    
    plt.subplots_adjust(top=1.3)
    plt.show()

7.Draw the lines on the original image

In [15]:
import pylab
for img_full_path in images_full_paths_lst:
    img = mpimg.imread(img_full_path) # read in a colored image
    
    img_gray = grayscale(img) # convert image into gray scale
    img_blured = gaussian_blur(img_gray, kernel_size) # apply gaussian to the grayed image
    img_canny = canny(img_blured, low_threshold, high_threshold) # apply canny edge detection to the blurred image
      
    vertices = get_polygon_region_of_interest_verticies(image.shape) # get 4 verticies for the polygon for the region of interest
    img_masked = region_of_interest(img_canny, vertices) # apply the poygon region on the canny image
    
    img_lines = hough_lines(img_masked, rho, theta, threshold, min_line_len, max_line_gap) # draw lines on the masked image
    img_with_marked_lines = weighted_img(img_lines,img) # draw the lines on the original image
    
    fig = plt.figure(figsize=(26, 12))
    fig.suptitle("image path: " + str(img_full_path), fontsize=20)
    
    plt.subplot(121)# 1 row, 2 cols, and this is the first figure
    plt.imshow(img)
    plt.title('Original Image',fontsize=20)
    
    plt.subplot(122)# 1 row, 2 cols, and this is the second figure
    plt.imshow(img_with_marked_lines, cmap='gray')
    plt.title('Image with marked lane lines',fontsize=20)
    
    img_name = img_full_path.rsplit('\\', 1)[1]
    pylab.savefig('test_images_output/' + img_name) #save the output images into the output images folder
    
    plt.subplots_adjust(top=1.3)
    plt.show()

Test on Videos

You know what's cooler than drawing lanes over images? Drawing lanes over video!

We can test our solution on two provided videos:

solidWhiteRight.mp4

solidYellowLeft.mp4

Note: if you get an import error when you run the next cell, try changing your kernel (select the Kernel menu above --> Change Kernel). Still have problems? Try relaunching Jupyter Notebook from the terminal prompt. Also, consult the forums for more troubleshooting tips.

If you get an error that looks like this:

NeedDownloadError: Need ffmpeg exe. 
You can download it by calling: 
imageio.plugins.ffmpeg.download()

Follow the instructions in the error message and check out this forum post for more troubleshooting tips across operating systems.

In [16]:
# Import everything needed to edit/save/watch video clips
from moviepy.editor import VideoFileClip
from IPython.display import HTML
In [17]:
def process_image(img):
    # NOTE: The output you return should be a color image (3 channel) for processing video below
    # TODO: put your pipeline here,
    # you should return the final output (image where lines are drawn on lanes)    
    img_gray = grayscale(img) # convert image into gray scale
    img_blured = gaussian_blur(img_gray, kernel_size) # apply gaussian to the grayed image
    img_canny = canny(img_blured, low_threshold, high_threshold) # apply canny edge detection to the blurred image
      
    vertices = get_polygon_region_of_interest_verticies(image.shape) # get 4 verticies for the polygon for the region of interest
    img_masked = region_of_interest(img_canny, vertices) # apply the poygon region on the canny image
    
    img_lines = hough_lines(img_masked, rho, theta, threshold, min_line_len, max_line_gap) # draw lines on the masked image
    img_with_marked_lines = weighted_img(img_lines,img) # draw the lines on the original image
    return img_with_marked_lines

Let's try the one with the solid white lane on the right first ...

In [18]:
white_output = 'test_videos_output/solidWhiteRight.mp4'
## To speed up the testing process you may want to try your pipeline on a shorter subclip of the video
## To do so add .subclip(start_second,end_second) to the end of the line below
## Where start_second and end_second are integer values representing the start and end of the subclip
## You may also uncomment the following line for a subclip of the first 5 seconds
##clip1 = VideoFileClip("test_videos/solidWhiteRight.mp4").subclip(0,5)
clip1 = VideoFileClip("test_videos/solidWhiteRight.mp4")
white_clip = clip1.fl_image(process_image) #NOTE: this function expects color images!!
%time white_clip.write_videofile(white_output, audio=False)
[MoviePy] >>>> Building video test_videos_output/solidWhiteRight.mp4
[MoviePy] Writing video test_videos_output/solidWhiteRight.mp4
100%|█████████▉| 221/222 [00:03<00:00, 56.18it/s]
[MoviePy] Done.
[MoviePy] >>>> Video ready: test_videos_output/solidWhiteRight.mp4 

Wall time: 4.51 s

Play the video inline, or if you prefer find the video in your filesystem (should be in the same directory) and play it in your video player of choice.

In [19]:
HTML("""
<video width="960" height="540" controls>
  <source src="{0}">
</video>
""".format(white_output))
Out[19]:

Improve the draw_lines() function

At this point, if you were successful with making the pipeline and tuning parameters, you probably have the Hough line segments drawn onto the road, but what about identifying the full extent of the lane and marking it clearly as in the example video (P1_example.mp4)? Think about defining a line to run the full length of the visible lane based on the line segments you identified with the Hough Transform. As mentioned previously, try to average and/or extrapolate the line segments you've detected to map out the full extent of the lane lines. You can see an example of the result you're going for in the video "P1_example.mp4".

Go back and modify your draw_lines function accordingly and try re-running your pipeline. The new output should draw a single, solid line over the left lane line and a single, solid line over the right lane line. The lines should start from the bottom of the image and extend out to the top of the region of interest.

In [20]:
def get_mid_x_in_vertices(vertices):
    vertices_x = []
    for point in vertices:
        for x,y in point:
            vertices_x.append(x)
        
    min_x = min(vertices_x)
    max_x = max(vertices_x)
    mid_x = (min_x + max_x) / 2
    return mid_x

def get_min_max_y_in_vertices(vertices):
    vertices_y = []
    for point in vertices:
        for x,y in point:
            vertices_y.append(y)
        
    min_y = min(vertices_y)
    max_y = max(vertices_y)
    return min_y, max_y

def poly_fit(lines):
    """This function gets the line coeffs by polyfitting points of lines"""
    xs = []
    ys = []
    for line in lines:
        for x1,y1,x2,y2 in line:
            xs.append(x1)
            xs.append(x2)
            
            ys.append(y1)
            ys.append(y2)
    line_coeffs = np.polyfit(ys, xs, 1)
    return line_coeffs

def get_left_right_lane_line_coeffs(lines, vertices):
    """This function separates the lines segments in hough transform into two parts.
    The first part is the left lane line segments, and the second part is the right lane line segments.
    The segments are separating using half of the polygon x coordinates which is (min_polygon_x + max_polygon_x)/2
    Finally, this function returns the left, and right lines coeffs."""
    left_line_segments = []
    right_line_segments = []
    
    mid_x = get_mid_x_in_vertices(vertices) + 10
    #separate the lines to two sections. The first is the left line segments, and the second is the right line segments.
    for line in lines:
        for x1,y1,x2,y2 in line:
            if x1 <= mid_x and x2 <= mid_x:
                left_line_segments.append(line)
            else:
                right_line_segments.append(line)
    
    left_line_coeffs = poly_fit(left_line_segments)
    right_line_coeffs = poly_fit(right_line_segments)
    return left_line_coeffs, right_line_coeffs

def get_img_lines_by_poly_fit_hough_lines(img, rho, theta, threshold, min_line_len, max_line_gap, vertices):
    """This function draws two full lines on an empty image"""
    lines = get_hough_lines(img, rho, theta, threshold, min_line_len, max_line_gap) # draw lines on the masked image
    left_line_coeffs, right_line_coeffs = get_left_right_lane_line_coeffs(lines, vertices)
    
    min_y, max_y = get_min_max_y_in_vertices(vertices)
    left_x0 = left_line_coeffs[0] * min_y + left_line_coeffs[1]
    left_x1 = left_line_coeffs[0] * max_y + left_line_coeffs[1]
    
    right_x0 = right_line_coeffs[0] * min_y + right_line_coeffs[1]
    right_x1 = right_line_coeffs[0] * max_y + right_line_coeffs[1]
    
    
    img_lines = np.zeros((img.shape[0], img.shape[1], 3), dtype=np.uint8)
    cv2.line(img_lines, (int(left_x0), min_y), (int(left_x1), max_y), [255,0,0], 10)
    cv2.line(img_lines, (int(right_x0), min_y), (int(right_x1), max_y), [255,0,0], 10)
    
    return img_lines
    
In [21]:
for img_full_path in images_full_paths_lst:
    img = mpimg.imread(img_full_path) # read in a colored image
    
    img_gray = grayscale(img) # convert image into gray scale
    img_blured = gaussian_blur(img_gray, kernel_size) # apply gaussian to the grayed image
    img_canny = canny(img_blured, low_threshold, high_threshold) # apply canny edge detection to the blurred image
      
    vertices = get_polygon_region_of_interest_verticies(image.shape) # get 4 verticies for the polygon for the region of interest
    img_masked = region_of_interest(img_canny, vertices) # apply the poygon region on the canny image
    
    img_lines_hough = hough_lines(img_masked, rho, theta, threshold, min_line_len, max_line_gap) # draw lines on the masked image
    img_lines_poly = get_img_lines_by_poly_fit_hough_lines(img_masked,rho, theta, threshold, min_line_len, max_line_gap, vertices)    

    
    fig = plt.figure(figsize=(26, 12))
    fig.suptitle("image path: " + str(img_full_path), fontsize=20)
    
    plt.subplot(131)# 1 row, 3 cols, and this is the first figure
    plt.imshow(img_masked, 'gray')
    plt.title('Canny Edges Image with region of interest',fontsize=20)
    
    plt.subplot(132)# 1 row, 3 cols, and this is the second figure
    plt.imshow(img_lines_hough, cmap='gray')
    plt.title('Hough transform lines Image',fontsize=20)
    
    plt.subplot(133)# 1 row, 3 cols, and this is the third figure
    plt.imshow(img_lines_poly, cmap='gray')
    plt.title('Poly fit Hough transform lines Image',fontsize=20)
    
    img_name = img_full_path.rsplit('\\', 1)[1]
    pylab.savefig('test_images_output/polyfitout_' + img_name) #save the output images into the output images folder
    
    plt.subplots_adjust(top=1.3)
    plt.show()
In [22]:
import pylab
for img_full_path in images_full_paths_lst:
    img = mpimg.imread(img_full_path) # read in a colored image
    
    img_gray = grayscale(img) # convert image into gray scale
    img_blured = gaussian_blur(img_gray, kernel_size) # apply gaussian to the grayed image
    img_canny = canny(img_blured, low_threshold, high_threshold) # apply canny edge detection to the blurred image
      
    vertices = get_polygon_region_of_interest_verticies(image.shape) # get 4 verticies for the polygon for the region of interest
    img_masked = region_of_interest(img_canny, vertices) # apply the poygon region on the canny image

    img_lines = get_img_lines_by_poly_fit_hough_lines(img_masked,rho, theta, threshold, min_line_len, max_line_gap, vertices)    
    img_with_marked_lines = weighted_img(img_lines,img) # draw the lines on the original image
        
    fig = plt.figure(figsize=(26, 12))
    fig.suptitle("image path: " + str(img_full_path), fontsize=20)
    
    plt.subplot(121)# 1 row, 2 cols, and this is the first figure
    plt.imshow(img)
    plt.title('Original Image',fontsize=20)
    
    plt.subplot(122)# 1 row, 2 cols, and this is the second figure
    plt.imshow(img_with_marked_lines, cmap='gray')
    plt.title('Image with marked lane lines',fontsize=20)
    
    img_name = img_full_path.rsplit('\\', 1)[1]
    pylab.savefig('test_images_output/polyfitline_' + img_name) #save the output images into the output images folder
        
    plt.subplots_adjust(top=1.3)
    plt.show()
In [23]:
def process_image_full_lines(img):
    # NOTE: The output you return should be a color image (3 channel) for processing video below
    # TODO: put your pipeline here,
    # you should return the final output (image where lines are drawn on lanes)    
    img_gray = grayscale(img) # convert image into gray scale
    img_blured = gaussian_blur(img_gray, kernel_size) # apply gaussian to the grayed image
    img_canny = canny(img_blured, low_threshold, high_threshold) # apply canny edge detection to the blurred image
      
    vertices = get_polygon_region_of_interest_verticies(image.shape) # get 4 verticies for the polygon for the region of interest
    img_masked = region_of_interest(img_canny, vertices) # apply the poygon region on the canny image
    
    img_lines = get_img_lines_by_poly_fit_hough_lines(img_masked,rho, theta, threshold, min_line_len, max_line_gap, vertices)  # draw lines on the masked image
    img_with_marked_lines = weighted_img(img_lines,img) # draw the lines on the original image
    return img_with_marked_lines

Now for the one with the solid yellow lane on the left. This one's more tricky!

In [24]:
yellow_output = 'test_videos_output/solidYellowLeft.mp4'
## To speed up the testing process you may want to try your pipeline on a shorter subclip of the video
## To do so add .subclip(start_second,end_second) to the end of the line below
## Where start_second and end_second are integer values representing the start and end of the subclip
## You may also uncomment the following line for a subclip of the first 5 seconds
##clip2 = VideoFileClip('test_videos/solidYellowLeft.mp4').subclip(0,5)
clip2 = VideoFileClip('test_videos/solidYellowLeft.mp4')
yellow_clip = clip2.fl_image(process_image_full_lines)
%time yellow_clip.write_videofile(yellow_output, audio=False)
[MoviePy] >>>> Building video test_videos_output/solidYellowLeft.mp4
[MoviePy] Writing video test_videos_output/solidYellowLeft.mp4
100%|█████████▉| 681/682 [00:15<00:00, 43.28it/s]
[MoviePy] Done.
[MoviePy] >>>> Video ready: test_videos_output/solidYellowLeft.mp4 

Wall time: 16.3 s
In [25]:
HTML("""
<video width="960" height="540" controls>
  <source src="{0}">
</video>
""".format(yellow_output))
Out[25]:

Writeup and Submission

If you're satisfied with your video outputs, it's time to make the report writeup in a pdf or markdown file. Once you have this Ipython notebook ready along with the writeup, it's time to submit for review! Here is a link to the writeup template file.

Optional Challenge

Try your lane finding pipeline on the video below. Does it still work? Can you figure out a way to make it more robust? If you're up for the challenge, modify your pipeline so it works with this video and submit it along with the rest of your project!

In [26]:
challenge_output = 'test_videos_output/challenge.mp4'
## To speed up the testing process you may want to try your pipeline on a shorter subclip of the video
## To do so add .subclip(start_second,end_second) to the end of the line below
## Where start_second and end_second are integer values representing the start and end of the subclip
## You may also uncomment the following line for a subclip of the first 5 seconds
##clip3 = VideoFileClip('test_videos/challenge.mp4').subclip(0,5)
clip3 = VideoFileClip('test_videos/challenge.mp4')
challenge_clip = clip3.fl_image(process_image)
%time challenge_clip.write_videofile(challenge_output, audio=False)
[MoviePy] >>>> Building video test_videos_output/challenge.mp4
[MoviePy] Writing video test_videos_output/challenge.mp4
100%|██████████| 251/251 [00:12<00:00, 20.24it/s]
[MoviePy] Done.
[MoviePy] >>>> Video ready: test_videos_output/challenge.mp4 

Wall time: 13.9 s
In [27]:
HTML("""
<video width="960" height="540" controls>
  <source src="{0}">
</video>
""".format(challenge_output))
Out[27]: